Important Molecules - Unit 1 Flashcards
Carbon Compounds
- Forms covalent bond (two atoms sharing a pair of electrons)
- Can form up to 4 bonds
- Important in proteins, lipids, nucleic acids and carbs
4 Common Functional Groups
- Hydroxyl (alcohol)
- Amine (protein)
- Carboxyl (protein)
- Methyl (protein)
Metabolism
- The sum of all reactions in an organism
- Consists of ‘pathways’ where one molecule is turned into another
- Two parts: Anabolism and Catabolism
Anabolism
- Things coming together
- Large molecule forms from small molecules with energy (ATP)
- Condensation reactions
- Ex. Photosynthesis
Catabolism
- Things breaking apart
- Large molecule turns into a small molecule and releases energy
- Hydrolysis reactions
- Ex. Digestion
Water
- Polar (particle charges on each end, bent shape)
- Covalent bonds
- Attraction between h and o molecules are hydrogen bonds
Waters Unique Properties
- Cohesive - Sticks to itself, ex. water transport in xylem
- Adhesive - Sticks to other polar molecules, ex. adhesion to cellulose in plants
- Thermal Properties
1. High specific heat capacity - A large amount of energy is required to heat up, and release to cool
2. High latent heat of vaporization - Large amounts of energy required to break h bonds and evaporate - Solvent properties - dissolves substances, dissolved polar covalent and ionic compounds, molecules form shells that prevent them from sticking together.
Hydrophilic vs. Hydrophobic
Hydrophilic - Substances that dissolve and adhere to water (salt)
Hydrophobic - Substances that can’t dissolve or adhere to water (lipids)
Transport of Substances in Blood Plasma
NaCl, AA, Glucose - Dissolved in plasma
O2 - Carried by hemoglobin
Fats, Cholesterol - Carried in Lipoprotein complexes in plasma
Carbohydrates
- Made of C, H and O, often end in ‘ose’
- Immediate energy source and energy storage
- Builds other molecules
- Used in cell membrane recognition and structures of plant cells
Types of Carbohydrates
Monosaccharides - 1 sugar unit, 3-7 C atoms, sweet taste, several polar -OH groups, soluble in water, ring structure
Disaccharides - 2 monosaccharides linked by condensation reactions, double ring structure
Polysaccharides - many monosaccharides
Examples of Polysaccharides
Cellulose - Unbranched, B D-glucose, chain alternating up and down, have ‘Cellulose Microfibils’ cellulose bonding parallel in hydrogen bonds
Starch - A D-glucose, same directions, two types:
1. Amylose - Plants store glucose in insoluble form, helix form
2. Amylopectin - Branched, glucose can be loaded or unloaded quickly due to many points
Glycogen - Branched, stores glucose in insoluble form in liver and muscle cells
Lipids
- Non-polar, mostly hydrophobic hydrocarbons
- Don’t form polymers
- Types of lipids:
Triglycerides, steroids, phospholipids
Triglycerides
- Fats - Solid at room temp, liquid at body temp
- Oils - Liquid at both temps
- Used for nutrition, energy storage and insulation
- Formed by 3 FAs and glycerol through a condensation reaction.
Fatty Acids
- A long chain of C and H with a Carboxyl group, 4-24 C long
- Saturated - Each C has an H, single bonded, straight chains, solid at room temp, animal sources
- Unsaturated - Monounsaturated has 1 double bond, polyunsaturated has 2 or more double bonds, kinked chains, liquid at room temp, plant sources
Cis-unsaturated FA - Naturally occurring , H on same side of the double bond, kinked chain
Trans-unsaturated FA - Not naturally occurring, H on opposite side of double bond, straight chain, solid at room temp.
Proteins
- Made up of AA’s containing an amino group, carboxyl group, carbon and R group
- Polypeptides are chains of AA’s that form proteins linked by condensation reactions
- Oligopeptide: 2-20 AA
- Polypeptide: 20+ AA
Diversity of Amino Acids and Polypeptides
- Unique R groups
- 20 different AAs, 9 we have to consume
- Some can be modified to make more AAs
- Polypeptide is a chain of AAs linked by ribosomes, there are 20^n possible sequences, range from 20-10,000 AAs
- Instructions are stored in base sequences
Shapes of Proteins
- Shape determines function, 2 shapes:
1. Globular (carrying), hydrophilic outside, hydrophobic inside, water-soluble, enzymes or carriers
2. Fibrous (structure), elongated chain, water-insoluble, physically tough and stretchy